Vaccination and occurrence of seizures in SCN1A mutation-positive patients: a multicenter Italian study

BACKGROUND: The relation between epileptic seizures and vaccinations is sometimes debated. In the present work, the impact of vaccination on seizure onset and clinical outcome of SCN1A mutation-positive patients is addressed. METHODS: Seventy-two patients diagnosed with Dravet syndrome or generalized epilepsy with febrile seizure plus, carrying SCN1A mutations or not, were included. Details on vaccination type, temporal relationship between vaccination and seizure occurrence, seizure type at onset and during development, cognitive functioning, and vaccination completion was obtained by reviewing clinical records. Patients were divided into two groups based on the temporal window between vaccination and seizure onset (proximate group: <48 hours; distant group: >48 hours). RESULTS: Vaccination-related seizures occurred in 25% of patients with SCN1A mutation and 18% of patients without the mutation (no significant difference). The proximate group showed an earlier age at seizure onset and a higher frequency of status epilepticus during development than did the distant group. No other significant differences were found. Subsequent vaccinations did not significantly alter the evolution of the disease. CONCLUSIONS: Results from this relatively small series provide evidence that vaccinations do not significantly affect clinical and cognitive evolution of Dravet syndrome and generalized epilepsy with febrile seizure plus patients even if they carry SCN1A mutations.